Pulper



Sept. 12, 1961 L. CAMPAGNANO PULPER 3 Sheets-Sheet 1 Filed Nov. 22, 1957Sept. 12, 1961 L. CAMPAGNANO PULPER 3 Sheets-Sheet 2 Filed Nov. 22, 1957//VVE TOR BY/ QW,W*M

ATTORNEYS p 1961 L. CAMPAGNANO 2,999,650

PULPEIR Filed Nov. 22, 1957 3 Sheets-Sheet 3 //VVE/VTOR BY f miw PMATTORNEYS 2,999,650 PULPER Leo Campagnano, Via Borromei 1 B/7, Milan,Italy Filed Nov. 22, 1957, Ser. No. 698,166 6 Claims. (Cl. 24146) Thisinvention relates to an improved and simplified apparatus for thedisintegration, separation and pulping of fibrous materials. Moreparticularly, this invention is concerned with the preparation of paperstock from wood, straw, paper machine broke, and other materials used inthe paper industry.

An object of my invention is to accomplish pulping with a minimum ofabsorbed horsepower input for a given production requirement. Anotherobject of my invention is to facilitate sustained continuous operationwith an absolute minimum of maintenance requirements. A further objectof my invention is to provide apparatus which is basically simple,thereby lowering the expense of initial investment. Still another objectof my invention is to provide apparatus which allows ready adaptationfor specific pulping applications. Another object of my invention is topermit the pulping of a wide variety of various materials withoutrequiring major alterations in the apparatus. A further object of myinvention is to provide a pulper which may also be employed to storepaper stock.

In the accomplishment of these and other objects of my invention in apreferred embodiment thereof, I employ a large elongated tub withrounded ends, divided into two channels by an upstanding midfeather. Atone end, there is a generally cylindrical pulping section formed by therounded end of the tub and separated from one side of the midfeather bya screen but communicating freely with the channel on the other side ofthe midfeather. At the other end of the tub from the pulping section acirculation propeller is so mounted as to produce general circulation ofstock around the midfeather through the pulping vat, and back throughthe screen.

A feature of my invention relates to the use of a rotor at the bottom ofthe cylindrical pulping area. This rotor is mounted on a vertical shaftextending through the bottom of the tub and is provided with twodifferent kinds of blades which create two substantially separate,distinguishable vortexes, or in another sense, cause two separate pathsof stock circulation, one radially outwardly along the bottom of thetub, and the other upwardly and more parallel to the axis of thecylider. These two separate paths of circulation, together with thegeneral circulation caused by the circulating propeller, tend toseparate the stock with the more refined particles moving eventuallyinto the outer radial flow path and out through the screen into thegeneral circulation. In this way the more finely subdivided componentsof the stock are permitted to hydrate under milder conditions ofagitation while the larger less dense components remain in the pulpingarea to be disintegrated.

Another feature of my invention is that the disintegrating action in thepulping area is not only attributable to the mechanical friction ofmaterial passing over the blades, but to the division of stockcirculation paths. This materially assists pulping by increasinghydraulic frictions.

An additional feature is that the continuous flow of stock around themidfeather and through the pulping area assists the separation of pulpedfibers causing them to pass more into the outer circulatory stock pathcaused by the pulper blades, while the larger pieces of stock yet to bedefibered tend to remain in the shorter vertical path where theyrepeatedly return to-the rotor blades. This results in a fasterrecycling of the material which need further disintegration. I

Still another feature of my invention the use of a 2 highly simplifiedpurely cylindrical pulping vat configuration requiring no deflectors orother odd shapes, and permitting the bottom of the vat to be flat.

Yet another feature of my invention is the use of a circulation vatattached to and in communication with a pulping vat. As soon as the pulpin the pulper has been reduced to a given dimension, it can flow intothe general circulation through the screen connecting the pulper to thecirculating section. The pulp in general circulation is thus given achance to absorb more water and is consequently more easilydisintegrated when the general circulation brings it back into thepulping section of the tub. A feature of this arrangement is that thecirculating sector can be of greater capacity and may eliminate the needof another vat after the pulper. Still another feature is the use of thecirculation vat for pulp storage and/ or the loading of paper machinebroke since the simplicity of the vat permits inexpensive constructionof large tubs or vats.

An additional feature of my invention is the ready adaptability of thecirculation section for eliminating impurities. The low velocity of thecirculating stock permits foreign matter to settle at the bottom of thecirculating section where it may be easily screened out.

Further objects and features of my invention will best be understood andappreciated from a detailed description of a preferred embodimentthereof, selected for purposes of illustration and shown in theaccompanying drawings in which:

FIG. 1 is a cross sectional view in side elevation of the pulper of myinvention;

FIG. 2 is a plan view thereof;

FIG. 3 is a cross sectional view in end elevation taken along the line3--3 of FIG. 1;

FIG. 4 is a partial plan View of the rotor;

FIG. 5 is a cross sectional view of the rotor taken along the lines 55of FIG. 4;

FIG. 6 is a cross sectional view of the rotor taken along the lines 66of FIG. 4;

FIG. 7 is a cross sectional view of the rotor taken along the lines 7-7of FIG. 4;

FIG. 8 is a cross sectional view of the rotor taken along the lines 8-8of FIG. 4;

FIG. 9 is a view in side elevation of the rotor taken along the lines 99of FIG. 4;

FIG. 10 is a cross sectional view taken along the lines 1010 of FIG. 4;and

FIG. 11 is a schematic drawing of the pulping vat showing stock flowpaths caused by the rotor of my invention.

Referring to the drawings, my invention includes in its generalorganization an elongated oval tub 10 having rounded ends 12 and 14. Anupstanding midfeather l6 partially divides the tub 10 into two channels18 and 20.

The tub 10 is filled with water and the material to be pulped isintroduced into a pulping section indicated at 22 at one end of the tub10. The pulping section 22 is cylindrical in configuration and isseparated from the rest of the tub by a screen 24 on one side of themidfeather 16, but communicates freely with the tub 10 on the other sideof the midfeather 16. At the bottom of the pulping section 22, I providea rotor 26 mounted on a shaft '36 rotating in suitable bearings in thebottom 28 of the pulper section 22. The rotor 26 in this preferredembodiment of my invention is driven by a motor (not shown) and belt 32attached to a pulley 34 which is keyed to the rotor shaft 36.

Water, or any other desired fluid, is continuously supplied to the tub10 by means of piping 38, having one inlet 40 controlled by a valve 42directly above the rotor 26, and another inlet 44 controlled by valve 46at the periphery of the pulping vat 22. Either or both inlets may beutilized to supply liquid and stock to the tub depending uponrequirements.

As the raw material is introduced into the pulping section 22, it isbrought into the churning currents caused by the rotation of rotor 26 atthe bottom of the'pulping vat. In this preferred embodiment the rotor26, as shown in detail in FIGS. 4-10, carries two different sets ofblades 48 and '50 alternately spaced around a'hub '52 mounted on thedrive shaft 36 at 54. The basic shapeof the blades 48 is that of anisosceles triangle diminishing in cross section toward the tip of theblade. The leading edge 56 of the blade 48 is the base of the isocelestriangle describing a convex are as it projects from the hub 52. Thetrailing edge 60 is pointed and is formed between the two sides 62 ofthegenerally isosceles cross section where they meet at the rear (seeFIG. 1.0).

Each of the blades 50 has a built up lug 64 cast integrally with hub 52which is then reduced as shown at 66 (see FIG. 6). The cross section ofthe blade 50 in the area indicated at 67 (see FIG. .8) is generallyrectangular with the width of the blades increasing toward the tip. Theleading edge 68 is convex and the trailing edge 70 is concave. The bladeterminates with a spoonshaped tip 72 which extends upwardly astindicatedat 74, the outer edge being provided with ribs76 to increase friction onthe stock.

The shape of blades 48 is similar to those of a centrifugal compressorand causes motion of stock as indicated by the flow lines 78 in FIG. 11along the bottom of the vat, thence deflected upwards along the sides.The concavity of blades 50 creates a second, coaxial but narrower vortexwith a more generally vertical flow path as shown by flow lines80 inFIG. 11 keeping stock in the most vigorously agitated area. Theportionof stock which comes in contact with the blades 50 is subject to afaster and more intense treatment because of the shorter flow path, themore violent change of direction, and the action of the grooves 76. Thetwo different flow patterns are of different velocities thereby creatingan action of hydraulic shear which for a givenpower input accomplishes asignificantlygreater amount of pulping than in conventional pulpers.

During these operations the material which requires frther pulping isseparated from the more finely disintegrated material because the lattertends to be more influenced by the centrifugal action-ofbladest48throwing it out into the vat away from the rotor 26. The coarsermaterial requiring additional pulping tendsrather to follow the shortervertical cycle 80. The morepulped particles thrown toward the peripheryof the pulping section 22 are fiushed'out of the pulping area (if smallenough) through the screen 24 and into the. general circulation in tubIt). This general stock flow or circulation is actuated by a propeller84 which is mounted on horizontal shaft extending through the end'wall14 of the tub It) and being supportedtthereinby suitable bearings. Flowis assured by confining the propeller within a properly dimensionedaperture in a .crosswall 86 and through which the propeller 84 impelsthe stock. The shaft $7 is driven by a 'belt 92 and motor 94. Thecontinuous flushing of the pulping section '22 of stock components whichare small enough to passthrough the screen 24 permits the rotor '26 toact mainly upon material requiring additional pulping. This 'bothincreases the efiiciency of pulping and"prevents'over-pulping.

'Theparticles carriedintothe general-circulation are further exposed tohydration and agitated, enhancing the pulping effects of the pulping vatwhich reduces the power required'to pulp a given quantity of material.This same relatively slow movement-of stock through the'pulping area "22and "aronnd-the -midfeather 16 in the general circlating section"permits ready removal of foreign matter which'tends to settle at-thebottom,-by placing -a screen 96 near tub end-14.

'Itis a particular feature 'of'my inventionz'that the screen 24 does notbecome clogged with over-sized particles. is due "to two things. First,the dual flow pattern of the stock in the pulper section 22 tends toseparate the larger components of the stock and return them toward thecenter. Second, the stock is swirling tangentially in the pulper section'22 with much greater velocity than mill is flowing through the screen24. This causes thelargerparticlesto break away from the screen andreturn to theipulpingzflowpaths.

Particles of stock brought back into the pulping section '22 by thegeneral circulation, if sutficiently pulped, are removed through adischarge outlet 98 located in the metal plate 28-near the-rotor 26. Adischarge pump 100 and valve 102 control outflow-through the pipe 104. Adownstream line oil the pump empties into a storage vat for pulpedmaterial neither of which are shown in the drawings. There is also aby-pass system indicated at 106 for returning stock to the pulper forfurther pulpmg.

Since numerous minor variations of this preferred embodiment of myinvention will now be apparent to those skilled in the art, it is not myintention to confine the invention to the precise form herein shown, butrather to limit it in terms of the appended claims.

Having .thus described and disclosed a preferred embodiment of myinvention, what I claim as new and desire to secure by Letters Patent ofthe United States is:

l. Pulping apparatus for paper stock comprising a tub, a section ofsaid'tub set aside for pulping but in communication with the remainingportions of said tub, means in said pulping section for subjecting paperstock to a vigorous hydraulic sheer pulping action including a pulpingrotor having first blades thereon for directing said stock outwardly andsecond blades thereon for directing said stock upwardly, and separatemeans for continuously withdrawing from said pulping section andcirculating around said tub under conditions of comparatively mildagitation stock components of a predetermined maximum particlesize.

2. -A pulper comprising a generally oblong tub with bottom,tsides andends, divided longitudinally by an upstanding midfeather, means forimparting general circulation .of-stock around said midfeather, pulpingmeans at .a pulping end of said tub for imparting a dual flow path tosaid stock one said path being radially outward from said means and theother said path being more nearly vertical, a substantially verticalscreen isolating said pulping means from said tub on the side of saidmidfeathert at the output of said general circulation from said pulpingstock,.and a discharge outlet for pulped stock at the bottom of saidtub.

3. A pulper comprising a tub including a bottom, sides and ends, anupstanding midfeather mounted on the said bottom clear of the said ends,a generally arcuate vertical screen connecting one end of saidmidfeather to one of said sides, a cross-wall between the other end ofsaid midfeather and the other of said sides, said cross-wall beingperforated to form an opening for passage of stock, a shaft coaxial withsaid opening, a propeller mounted fast on said shaft to rotatetherewith, means for rotating said shaft causing a general circulationaround said midfeather in a rotational direction flowing through saidscreenout of said end bounded thereby, and pulping means in said tub onthe discharge side of said propeller said means imparting twosubstantially separate flow paths comprisingtan outer vortex and aninner vortex, said outer vortex having the same rotational direction andcoinciding ingpart with said general circulation.

4. A pulper comprising a tub including a bottom, sides and ends, an.upstanding midfeather mounted on the bottom..,clear of the vends, agenerally vertical screen connecting one end ofsaid midfeather to one ofsaid sides, a vertical shaft through the bottom of said tub between thescreen end of said midfeather and the tub end, a .rotorwithrafirstisetaand second setof blades mounted fast to said shaft to rotatetherewith, said first blades constructed to promote a stock flow pathgenerally outwardly from said rotor, said second blades constructed topromote a more vertical stock flow path, means for continually flushingstock in the flow path created by said first blades out of said paththrough said screen and around said midfeather a discharge outlet forstock at the bottom of said tub.

5. A pulper comprising an elongated tub with bottom, sides and ends, apulping section and a circlating section in said tub, an upstandingmidfeather dividing said circulating section longitudinally, means forcreating general stock circulation around said midfeather and throughsaid pulping section, said pulping section separated from saidcirculating section by a screen, pulping means in said pulping sectionincluding a rotor, first and second blades on said rotor, said secondblades adapted to cause a generally vertical stock current path, saidfirst blades adapted to cause a generally radial stock current path insaid pulping section in the same rotation direction as the generalcirculation, and a discharge outlet for said tub.

6. In a pulper, a vat, a rotor, means for rotating said rotor in saidvat in contact with paper stock, first blades on said rotor presenting asubstantially vertical surface 6 to said stock for driving said stock inan outward radial path, and second blades on said rotor presenting anupwardly slanting surface to said stock for driving said stock in a morevertical path, whereby the smaller and more disintegrated components ofsaid stock are directed in a path radially outward from said rotor thenupwardly and around said vat; means operatively associated with saidrotor for directing the larger and less disintegrated components of saidstock in a more vertical and shorter circulatory path upwardly from andreturning to said rotor; and means for continuously withdrawing stockcomponents smaller than a certain maximum size from said radial path outof said vat.

References Cited in the file of this patent UNITED STATES PATENTS1,692,602 Witham Nov. 20, 1928 1,768,735 Beers July 1, 1930 1,811,741Bishop June 23, 1931 2,424,726 Wells July 29, 1947 2,434,449 Wells Jan.13, 1948 2,719,462 Fowler Oct. 4, 1955 2,902,228 Higer Sept. 1, 19592,911,334- Stuck Nov. 3, 1959

